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new to welding aluminum with spool gun

Hi all

So i have a lincoln 180c welder and a spool gun to go with it to weld alloy.
I'm new to welding alloy and steel but figured out how to weld steel pretty quickly and now welding steel on a daily bases for about a month.
I fabricate gates and fences made out of alloy or steel and have to do alot of miter joints for the corners.
I haven't been able to make anything out of alloy yet since i only got my spool gun 1 week ago.
So i tried welding alloy and its alot harder than i thought. Yes i have straight argon and have set the settings that's written on the inside of the welder but it seems to blow holes because its to hot and when i turn it down the wire sometimes pushes the gun back and doesn't get an arc.
I want to know if anybody has any good tips on how to set a spool gun connected to a lincoln 180c that is used to weld 1.6mm thick aluminum box tubing.
Also what is the best way to weld miter joins because i am totally failing on welding aluminum miter joints. Should i bevel the outside joint and weld that or should i leave it as it is and just powder coat straight over that or will it show?
Any advice will be great as iv got alot of alloy welding to do and customers are not happy when i turn the jobs down.

Re: new to welding aluminum with spool gun

Hello and welcome.

Alum needs to be welded hot and fast. Expect to travel 2 to 3 times faster than when you do steel. To do .062 alum, you are on the bottom edge of what you can typically do with a spoolgun, so blow thru isn't unexpected when starting out. Setting on the door are probably close. For mig alum you need to use more voltage and a faster wire speed than you do with steel, as well as going faster in your travel speed.

One common error is guys with mig want to "drag" the weld, usually so they can see better. With alum mig you really have to push on thin stuff to limit penetration and keep good gas coverage. To see well you have to get your head in front of the gun and look down the barrel.

Using a heat sink to back up your work may help in some situations. Working with cold material will also help. Remember alum is a great heat sink, and any other welds near by will heat up the material, possibly acting like you turned the voltage up slightly on your machine. Lats thing you need is more "heat" on 1/16".

You can "fine tune" your heat slightly by varying your stickout. Remember that the farther away the gun is from the work, the "colder" the weld will be using the same settings. Between this and making small adjustments to your voltage and wire speed ( here's where an infinite voltage machine can really help) you can dial in your settings.

Alum mig is NOT like welding steel with mig. It's a lot harder to master. If you can't do a decent job controlling basic things like travel speed, stickout, gun angle and so on, you might have chance. Inconsistencies will be magnified at the speeds you have to move at to do mig alum. If you can't be consistent on steel, you will have a much tougher time with thin alum.

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No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

Re: new to welding aluminum with spool gun

Thanks for your reply it has given me some great tips and i am a quick learner and will take all of that on board.
I noticed when i 1st started welding alloy that my main problem was trying to use a cursive hand motion and that left a big ugly weld or burnt most the time.
Today i turned the wire feed speed on low and the heat down and gave it a straight slow run but the penetration wasn't to my satisfactory.
After reading that my main problem is going to slow than that is what i will work on and keep the settings as per the guidelines and adjust slightly of that because when i weld with steel the guidelines are the exact volt and speed that i need.

Thanks alot for your help.
Not to be a pain but if you have pointers on welding miter joints with 1.6mm alloy that will be ever so helpful.

Re: new to welding aluminum with spool gun

Biggest issue with miter joints is usually the knife edge outside corners. Many times guys will cut the miter, then file off the knife edge back to full thickness material. Often this may require the pieces be cut a hair on the long side to allow for this.

Another possible way to to change your joint design. Instead of cutting a miter, say on angle, cope the joint instead. Again I'll swipe one of Dhem's great picts of a good coped joint as an example. If you are doing tube, you cut and but the joints, then cut "plugs" and weld them in. Again Dehm just posted up some great examples of doing this on his latest project. Though it's steel vs alum, the idea is the same.

I forgot to include motions in my suggestions above. What you found is very true. Circles or an e shape tends to make you stay in the same place longer for a give travel speed. I have to slow down when I run a straight stringer vs running an circular motion. Many times like when welding thin outside corners, it's almost impossible for me to move fast enough and do a e motion and keep the circles small enough and close enough together to get good results. A straight push works better. My motions are secondary. I do everything based on what I see the puddle doing and react as needed to manipulate the puddle as needed based on what I see. I speed up, slow down, increase or decrease my stickout, change my motion or gun angle, many times all at the same time. The end result however doesn't show any of this. All you see is one nice even consistent bead. I like to do a demo where I go from a circular pattern to a "C" or "Z" pattern then on to a straight stringer, all without ever stopping the bead I'm running for students. When I'm done, you usually can't spot where I changed my motions. The point being it's not what shape or pattern that I'm using that determines the way the weld looks, it's the fact that I can see and manipulate the molten metal to get the results I want. That just takes practice and hood time, and I haven't yet found a short cut that eliminates this.

Last edited by DSW; 11-30-2013 at 12:13 PM.

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No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!

Re: new to welding aluminum with spool gun

Ok so i made some alloy panels today and done alot of spot welds to just hold some parts as that's all that's needed. I couldn't for the life of me get the right setting. It was either to hot and blows holes through, to cold and leaves a turd weld, main problem i had when welding full passes was the temperature was set right and the wire feed set right but when i got half way on the weld the wire from the gun would just melt and drip onto the work piece sorta like the wire feed wasn't pushing the wire. There was also alot of black welds when i was spot welding so i thought the alloy was dirty even tho its straight from the manufacturer so i hit it with acetone twice until my rag wasn't black and then tried again. Still ended up with black welds so i grabbed my grinder with a flap disc and went crazy on a join and then had a go and to my amazement still black welds.
Now what im thinking after all these **** welds is that my gun and the wire connections are wrong. The manual i got with the gun to connect it looked like a kid was drawing a pic of how his dad connects his dildo so i just figured out how to connect the wires but now don't think its right.
I cant find any you tube vids about how to wire the gun or even the manual of the net.

Re: new to welding aluminum with spool gun

Originally Posted by slowrx

main problem i had when welding full passes was the temperature was set right and the wire feed set right but when i got half way on the weld the wire from the gun would just melt and drip onto the work piece sorta like the wire feed wasn't pushing the wire. There was also alot of black welds when i was spot welding so i thought the alloy was dirty even tho its straight from the manufacturer so i hit it with acetone twice until my rag wasn't black and then tried again. Still ended up with black welds so i grabbed my grinder with a flap disc and went crazy on a join and then had a go and to my amazement still black welds.

Black smutz is typical of mig welding alum. There are ways you can reduce it, but eliminating it usually doesn't happen. Some where I have a link to a good article on reducing black soot on alum mig, but I can't find it on this computer.

The way you describe the wire looking, sounds like you are too low on your voltage and wire speed. Mig alum is a spray arc process. You won't get the nice bacon frying sound you hear with steel. Instead you hear what I can best describe as a hiss instead. The wire melts almost as soon as it leaves the tip and literally sprays molten metal at the piece like paint. If you are seeing drips or the wire advancing and retreating, chances are you are not yet up in spray mode.

Your 180 maxes out on 1/8" alum. Usually when people ask how to set a machine like that for 1/8", I usually suggest they max out both the wire and the voltage and then adjust down vs trying to go up to find the settings they need. On 1/16", you will be below maximum. I'd take the factory suggested settings and bump them up slightly, then come down as you adjust.

1/16" alum is right on the bottom edge of what is doable by most people with mig. What you are experiencing is common, especially if your mig skills aren't great to begin with.Short welds won't make this any easier since you will almost be finished with the weld as soon as you hit the trigger if you are moving fast enough with your travel speed. The big bulky spool gun messes with people as well. All that weight and mass makes it tough to get used to moving fast enough as well as getting your gun angle correct.

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No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth!